The North Korean soldier who defected to South Korea through the Joint Security Area Monday is still in a critical condition, with his stomach filled with parasites, the attending doctor said Wednesday.

The soldier has successfully undergone a second round of surgery at Ajou University hospital earlier in the day, which lasted for about three-and-a-half hours, from 9:30 a.m. to 1 p.m. He is still in a critical condition, according to Lee Cook-jong, the physician who treated him.

The operation concluded with the removal of a bullet lodged in the abdominal wall, Lee said.

“We are struggling with treatment as we found a large number of parasites in the soldier’s stomach, invading and eating into the wounded areas,” Lee said. “We have also discovered a parasite never seen in Koreans before. It is making the situation worse and causing tremendous complications.”

The parasites include a species of roundworms, the doctor said, which the soldier might have contracted before the gunshot wound.

Roundworms may be contracted by eating vegetables fertilized with human manure. Human feces produced from eating these plants may then be recycled to grow more vegetables, which increase the roundworm population. Roundworms can cause malnutrition and block the intestine, causing pancreatitis and appendicitis. These parasites may also cause peritonitis if it penetrates a vulnerable part of the intestine. If left untreated, peritonitis can spread rapidly into the blood and other organs, leading to multiple organ failure and death.

Like the North Korean soldier, many North Koreans are likely to be infected with parasites, experts say.

“I don’t know what is happening in North Korea, but I found many parasites when examining other defectors,” said Professor Seo Min at the Dankook University Medical School. “In one case, we found 30 types of roundworms in a female defector. The parasite infection problem seems to be serious even if it does not represent the entire North Korean population.”

The JSA soldier’s small intestine is currently ruptured, contaminated with fecal matter, and infected with parasites, according to Lee.

“He has everything that he could have,” Lee said. "It is very likely that the prognosis will be worse than other general trauma patients as he has been in a state of shock induced by heavy bleeding and we expect to deal with many complications.”